IP network interfaces are called as core interfaces,access interfaces or PE-CE interfaces. But in WIMAX, interfaces are named as depicted belows:-
1. R1 Interface:- This is actual wireless interface which connects Mobile Subscriber to BS(Base Station).
2. R2 Interface:- This is the logical interface with CSN(Core Service Network). In case of Mobile IP.
3. R3 Interface:- Interface between ASN(Access Service Network) and CSN(Core Service Network).All the radius messages are exchanged on this interface.
4. R4 Interface:- This is the logical interface between ASN-Gty(Access Service Network). This interface is used during handovers in romaing.